The purpose of this NHLBI Institutional Research Training Program at UCSD, which has maintained a positive record over some 20 years, remains unchanged. The goal is to prepare carefully selected physicians of high investigative potential, who have completed their clinical training, for productive research careers. The centerpiece of this training effort is direct involvement by trainees in research, under the preceptorship of experienced scientists who have a record of productive, well-funded investigation and a demonstrated devotion to research training. Trainees participate actively in all phases of the investigative process: formulation of sound hypotheses, mastery of fundamental concepts and technics, background reading, didactic offerings, hands-on experience at the bench and discussions with preceptors and collaborating investigators. Rigorous attention to experimental design, including biostatistical considerations, is emphasized, as are the writing of protocols; direct performance of the research; data analysis and interpretation; ethical considerations in research; and the preparation of verbal and written presentations and publications. Trainees investigative activities are reviewed by the Preceptor, collaborating investigators, at Divisional Research Conferences, by visiting consultants and, twice each year, by the Divisions Education Committee. The outcomes of trainees who have completed this Training Program have been, and continue to be, positive. The majority of our graduates have entered productive academic-investigative careers at institutions throughout the United States; and a number have achieved leadership positions in Pulmonary Medicine.